#include <iostream>

long double probability(unsigned numbers, unsigned picks);

int main(void){
	using namespace std;

	double total, choices;
	cout << "Enter the total number of choices on the game card and\n"
			"the number of picks allowed:\n";
	
	while ((cin >> total >> choices) && choices <= total){
		cout << "You have one chance in " << probability(total, choices) << " of winning.\n";
		cout << "Next two numbers (q to quit): ";
	}
	cout << "bye\n";

	return 0;
}

long double probability(unsigned numbers, unsigned picks){
	long double result = 1.0;
	long double n;
	unsigned p;

	for (n = numbers, p = picks; p > 0; n--, p--)
		result *= n/p;
	
	return result;
}